Investigating the genetic bases of brain plasticity will help us to understand both the plastic processes of healthy learning and memory during development and aging, and the loss of plasticity that occurs in brain aging and neurodegenerative disorders. Because of the similarities between birdsong and human language, the songbird is an ideal model system in which to study this type of plasticity. This is in part because, unlike humans who have no closely related species with language, the songbird radiation includes hundreds of species with variations in song plasticity. For instance, the male zebra finch has a static adult song that is copied during youth from a tutor male. Even some species closely related to the zebra finch do not follow this song learning paradigm. The yellow-winged pytilia is an estrildid finch like the zebra finch, but unlike the zebra finch, it has an innate song from birth. Another Estrildid, the red avadavat, will imitate other species'songs in addition to its own species-specific song. Even more striking is the song learning paradigm of the starlings that can add songs to their repertoire throughout their adult lives. What are the genetic mechanisms responsible for these fascinating differences in vocal plasticity? Are these mechanisms of plasticity the same throughout development and adult life? The ultimate goal of the experiments described below is to answer these questions by developing and applying methods of comparative genomics to identify gene sequences associated with vocal learning ability in songbirds. This will be done by 1) validating methods for inter-species microarray analyses, looking for CNV, and controlling for divergence effects in comparative microarray hybridizations. 2) testing whether zenk expression in songcontrol areas is related to the level of adult plasticity 3) investigating the genomic basis of variations in vocal plasticity in estrildid finches. Understanding brain plasticity, particularly plasticity involved in development and aging, is essential to our ability to improve and lengthen our cognitive lives. This research into vocal plasticity will not only help elucidate how humans learn and process language, but it will also help to add to our knowledge of general brain plasticity. Strokes, neuro-degenerative disorders, and cognitive decline are all associated with human aging. As the American population grows older each year, it is important to invest in understanding the complex processes of brain aging, so that we can help to prevent and treat these diseases. Understanding and preventing these diseases will have a incredible effect on public health and healthcare spending.